21245633670 has 128 divisors (see below), whose sum is σ = 52668112896. Its totient is φ = 5482832256.

The previous prime is 21245633627. The next prime is 21245633671. The reversal of 21245633670 is 7633654212.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21245633671) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 57889827 + ... + 57890193.

It is an arithmetic number, because the mean of its divisors is an integer number (411469632).

Almost surely, 2^21245633670 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21245633670, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26334056448).

21245633670 is an abundant number, since it is smaller than the sum of its proper divisors (31422479226).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21245633670 is a wasteful number, since it uses less digits than its factorization.

21245633670 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 874.

The product of its (nonzero) digits is 181440, while the sum is 39.

The spelling of 21245633670 in words is "twenty-one billion, two hundred forty-five million, six hundred thirty-three thousand, six hundred seventy".